Is Dioecy Associated With Fleshy Fruit?

The floras of the northeastern U.S. and California were analyzed with respect to the question whether dioecy is associated with fleshy fruit. These analyses control for mode of pollination, woodiness, and flower color. Weak associations between dioecy and fleshy fruit were observed, unconvincing because of the difficulty of controlling for phylogenetic constraint. Other such studies are reviewed, however, and, because the better studies all do show a weak association, it is concluded that the weak association may be real. An ecological explanation is postulated and defended. The much stronger association between dioecy and floral biology is noted.